Thrusting devices for rolling mills



.Fune 20, 1967 TOSHIYUKI KAJIWARA 3,326,028

THRUSTING DEVICES FOR ROLLING MILLS Filed March 24, 1964 2 Sheets-Sheet l InvEnToR Tos 'flyu Ki HaSuo ATTORNEY June 1967 TOSHIYUKI KAJIWARA 3,325,023

THRUSTING DEVICES FOR ROLLING MILLS 2 Sheets-Sheet 2 Filed March 24, 1964 as ms I .3 Q 5 Q mQ mQ V. 3 M9 W v9 a N02 V 9 2 3 9 M Q Q Q m at IhvEnTOR roshh uk; y; (9013b "1.

ATTORNEY United States Patent 3,326,028 THRUSTING DEVICES FOR ROLLING MILLS Toshiynki Kajiwara, Hitachi-ski, Japan, assignor to Hitachi, Ltd., Chiyoda-ku, Tokyo, Japan, a corporation of Japan Filed Mar. 24, 1964, Ser. No. 354,384 Claims priority, application Japan, Apr. 1, 1963, 38/ 16,147 12 Claims. (Cl. 72-240) The present invention relates to rolling mills and more particularly to a thrusting device for rolling mills in which an amount of stroke of rolls relative to each other is adjustable by means of a hydraulic cylinder.

Thrusting devices of the type heretofore employed in rolling mills for the rolling operation of strips include electrically driven types and hydraulically driven types. In conventional thrusting devices of electrically driven type, thrusting screws are rotated for thrusting operation by an electric motor by way of a reduction gearing, worms and worm wheels. However, the thrusting devices devices of electrically driven type are defective in an excessively great reduction ratio and an extremely poor power transmission etficiency attributable to a screw mechanism incorporated in the last stage of power transmission. Other drawbacks involved in the conventional devices of the type include the necessity of a powerful thrusting motor and a large-sized reduction mechanism which results in an expensive rolling mill and inconvenience in maintenance and inspection thereof. On the other hand, conventional thrusting devices of hydraulically driven type are composed of a hydraulic cylinder, a pilot valve and drive means for actuating the piston of the pilot valve. Thus, the device of hydraulically driven type has a very simple structure and can be manufactured at low cost since it does not require any bulky thrusting mechanism such as is used in the device of electrically driven type. While the conventional device of hydraulically driven type is advantageous in this respect, difliculties encountered in this device are that the piston of the pilot valve is adjusted either directly by hand or by some driving means, but due to varying load conditions and different fluid resistances, it is diifcult to effect a required parallel movement of rolls relative to each other and it is therefore impossible to give a proper amount of stroke thereto.

Therefore, the rolling mill with the conventional thrusting device of hydraulically driven type has only been used for a rolling operation such as of aluminum foils in which the thickness of blanks is quite small compared with the diameter of rolls and any inter-roll clearance is not set prior to the rolling operation.

Therefore, the primary object of the invention is to provide an improved thrusting device of hydraulically driven eype in which resetting means is provided so as to facilitate the positioning of rolls and to provide an accurate amount of stroke thereof.

According to the invention, there is provided a thrusting device for a rolling mill comprising a housing, a pair of working rolls rotatably supported in said housing, a pair of auxiliary rolls rotatably supported in said housing at positions outwardly of said working rolls so as to urge said working rolls inwardly from behind thereof, and a pair of hydraulic mechanisms each having a hydraulic cylinder operable to urge one of said working rolls toward the other through one of said auxiliary rolls, a pilot valve for controlling hydraulic pressure interposed midway of a hydraulic fluid passage between said cylinder and a hydraulic pump, resetting means operatively associated with said pilot valve for actuating the same, and drive means for driving said resetting means.

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According to the invention, there is further provided a thrusting device for a rolling mill comprising a housing, a pair of working rolls rotatably supported in said housing, a pair of auxiliary rolls rotatably supported in said housing at positions outwardly of said working rolls so as to urge said working rolls inwardly from behind thereof, and a pair of hydraulic mechanisms each having a hydraulic cylinder operable to urge one of said working rolls toward the other through one of said auxiliary rolls, a pilot valve for controlling hydraulic pressure, a piston member interposed midway of a hydraulic fluid passage between said cylinder and said pilot valve for making a movement proportional to that of a ram in said cylinder, resetting means operatively associated with said piston member for actuating the same, and drive means for driving said resetting means.

The device according to the invention has marked advantages over those of conventional design in that the parallel movement of the roll toward and away from the opposite roll can remarkably accurately be made and a precise amount of stroke can be obtained.

There are other projects and particularities of the invention which will become obvious from the following description with reference to the accompanying drawings, in which:

FIG. 1 is a schematic side view of an embodiment of a thrusting device of the invention adapted for a rolling mill, with parts in vertical section;

FIG. 2 is a partial front view of the device of FIG. 1, the view being taken along the line AA in FIG. 1 and with parts also in vertical section; and

FIG. 3 is a schematic side view of another embodiment of the invention, with parts in vertical section.

FIGS. 1 and 2 show an embodiment of a thrusting device of the invention as adapted to a quadruple rolling mill. In FIG. 1, it will be seen that working rolls 4 and 5 are disposed in a roll housing 1 and forced inwardly toward each other by auxiliary or backing rolls 2 and 3, respectively. The working rolls 4 and 5 are disposed on opposite sides of a plane 6 on which strips (hoops) are made to pass. The upper working roll 4 is forced downwardly from behind by the upper auxiliary roll 2, and the respective rolls 2 and 4 are journalled at opposite ends in roll chocks 8 and 7 which are vertically movably mounted in the roll housing 1. The lower working roll 5 is forced upwardly from behind by the lower auxiliary roll 3, and the respective rolls 5 and 3 are journalled at opposite ends in roll chocks 9 and 10 mounted in the housing 1.

The roll chocks 7 supporting the working roll 4 are urged upwardly by hydraulic pressure balancing rams 11 actuated by hydraulic means not shown, while the roll chocks 8 supporting the auxiliary roll 2 are urged upwardly by hydraulic pressure balancing rams 12 actuated by hydraulic means also not shown. A hydraulic cylinder 13 is disposed above each of the roll chocks 8 supporting the upper auxiliary roll 2. A thrusting ram 14 received in each hydraulic cylinder 13 extends downwardly for pressure engagement with each roll chock 8 supporting the auxiliary roll 2, and the rams 14 are moved upwardly and downwardly in the cylinders 13 to cause upward and downward movement of the rolls 2 and 4.

A rod 15 is connected with each thrusting ram 14 and extends upwardly therefrom. A lever 20 is pivotally supported on each rod 15 by a pivot 21 and has one end thereof brought into contact with the upper end of a pilot piston 17 operatively received in a pilot valve 16 for controlling hydraulic pressure, while the other end thereof is connected to a nut 19 which is in threaded engagement with a screw 18 for upward and downward movement by the rotation of the screw 18. A worm wheel 22 is firmly fixed at the lower end of the screw 18, the upper end of which is supported in a bearing 23 mounted in a frame not shown. Each pilot piston 17 is normally urged upwardly by a spring 24 disposed therebelow. Motors 25 and 26, which may be electric motors, are connected with each other by a magnetic clutch 27 and disposed in tandem on the top of the roll housing 1 and in parallel with the longitudinal direction of the rolls as shown in FIG. 2. The motors 25 and 26v have their shafts extended to the right and left, respectively, as viewed on FIG. 2, and a Worm gear 28 is mounted at the extremity of each shaft for meshing engagement with the corresponding worm wheel 22. The motor 25 serves to operate the hydraulic mechanism shown in FIG. 1, while the motor 26 serves to operate the hydraulic mechanism not shown therein, so that both can cooperatively act to effect the parallel movement of the upper auxiliary roll 2 relative to the lower rolls.

An accumulator 29 for the supplied fluid is provided at a suitable position on a conduit 33 through which the hydraulic fluid or oil drawn out of a reservoir 31 by means of a hydraulic pump 30, driven by an electric motor not shown, is supplied through the pilot valves 16 into the hydraulic cylinders 13. A conduit 32 is provided to connect the interior of each pilot valve 16 to the interior of the cylinder 13 associated therewith. The hydraulic fluid discharged out of the pilot valve 16 returns to the reservoir 31 by way of a conduit 34.

The thrusting device described in the above and shown in FIGS. 1 and 2 operates in the following manner. When it is intended to depress the upper working roll 4 towards the lower working roll in parallel relation thereto, the motors 25 and 26 are simultaneously driven. Since both of the motors 25 and 26 are mechanically connected with each other by means of the magnetic clutch 27 interposed therebetween, there is no possibility of causing any difference in their speeds of rotation and the screws 18 are rotated by the motors through the worm wheels 23 and the worms 22 in a direction such that the nuts 19 are urged downwardly depending on a necessary amount of stroke. In the mechanism the lever 20 is made to rotate about the pivot 21 to disengage the pilot piston 17 so that the piston 17 is urged upwardly by the spring 24 to open the valve 16 and hydraulic pressure is admitted into the cylinder 13 by way of the conduits 33 and 32. Thus, the thrusting ram 14 is urged downwardly and at the same time the lever 20 pivotally connected with the rod 15 is also forced downwardly to thereby force the pilot piston 17 downwardly. Since the valve 16 is thereby closed, the thrusting ram 14 is secured in place. The amount of oil fed into the cylinder 13,, that is, the amount of stroke is thus determined by the amount of rotation of the motor 25. Since the mechanism associated with the motor 26 is the same as that associated with the motor 25 and operates in the same manner, the same amount of rotation of the motors 25 and 26 can provide the same amount of stroke on either side and thus the upper working roll can be moved in parallel relation all over and can be set at the same level.

When it is desired to urge the upper working roll upwardly, the motors may be rotated in the opposite direction. Then, the nuts 19 move upwardly and the pilot pistons 17 are urged downwardly to provide communication between the conduits 32 and 34. The pressure in the cylinders 13 is thereby exhausted, and the roll chocks 7 and 9 supporting the upper working roll and upper auxiliary roll are urged upwardly away from the roll chocks 9 and supporting the lower working roll and lower auxiliary roll by the hydraulic rams 11 and 12, respectively. Thus, the thrusting rams 14 move upwardly by an amount depending on the amount of rotation of the motors 25 and 26. When it is desired to operate only one of the two mechanisms, the magnetic clutch 27 may be deenergized and only the motor on the required side may be driven.

FIG. 3 shows another embodiment of the invention, in which like reference numerals are employed to designate like parts as appearing in the embodiment of FIGS. 1 and 2. In FIG. 3, there is shown a roll housing 1 in which working rolls 4 and 5 are disposed and forced toward each other by auxiliary or backing rolls 2 and 3, respectively. The respective upper rolls 2 and 4 are journalled at opposite ends in roll chocks 8 and 7 provided in the roll housing 1. The lower working roll 5 and the lower auxiliary roll 3 are journalled in roll chocks 9 and 10, respectively, which are vertically movable in the roll housing 1. Reference numerals 11 and 12 denote hydraulic pressure balancing rams for the lower working roll 5 and the lower auxiliary roll 3, respectively.

A hydraulic cylinder is disposed below each of the roll chocks 10 for the lower auxiliary roll 3. A thrusting ram 101 received in each hydraulic cylinder 100 extends upwardly for pressure contact with each roll chock 10 for the lower auxiliary roll 3. In a hydraulic fluid supplying system from a reservoir 118 to each hydraulic cylinder 100, a piston member 102 is interposed between a pilot valve 103 and the cylinder 100. A lever 108 is pivotally supported at a point 109 by a piston rod 104 of the piston member 102. One end of the lever 108 is in engagement with the lower end of a pilot piston 105 received in the pilot valve 103, while the other end of the lever 108 is operatively connected with a nut 107 which is in threaded engagement with a screw 106 for upward and downward movement 'by the rotation of the screw 106. The pilot piston 105 is abutted at its upper end by a spring 110 and normally urged downwardly by the spring 110.

Hydraulic pressure is supplied into the pilot valve 103 by way of a supply conduit 111 and discharged therefrom by way of a discharge conduit 112. The pilot valve 103 is connected with the piston member 102 through a conduit 113. Two motors 114 and 115, which may be electric motors, are connected with each other by means of a magnetic clutch 116 interposed therebetween. The motor 114 serves to operate the hydraulic system illustrated in FIG. 3, while the motor also serves to operate the hydraulic system not shown. Thus the motors 114 and 115 cooperate in efiecting a parallel movement of the auxiliary roll 3. An accumulator 117 is provided on a conduit connecting the piston member 102 with the cylinder 100 and is operative Whenever excessive pressure resulting from miss-rolling is exerted on the cylinder 100. Reference numeral 119 denotes an accumulator for the hydraulic fluid being supplied. Conduits 123 and 124 with respective valves 121 and 122 are connected to the conduit 120 well downstream of the piston member 102, lay-passing the pilot valve 103 and the piston member 102 so that these conduits may be utilized by opening and closing the valves 121 and 122 when a great relative stroke is required in the roll as in a case of a rolling operation for a different strip thickness. Thu-s, the change-over may be easily and rapidly effected without operating the piston member 102. By the provision of these conduits 123 and 124, itis possible to make the piston member 102 quite smaller than the cylinder 100 and the piston member 102 can be solely used for close adjustment of the roll stroke.

The second embodiment shown in FIG. 3 operates in the following manner. When it is desired to make the relative parallel movement of the rolls towards each other, the motors 114 and 115 may be simultaneously driven. There is no difference in the speeds of rotation of both motors since they are mechanically connected with each other by the magnetic clutch 116. In the mechanism associated with the motor 114, the motor 114 is rotated in a direction such that the screw 106 is thereby made to rotate to move the nut 107 downwardly. Then the lever 108 is made to rotate about the pivot 109 to thereby urge the pilot piston 105 upwardly. Thus, the conduits 111 and 113 are made to communicate with each other and hydraulic pressure is supplied into the piston member 102. The piston rod 104 is thereby urged downwardly to force the free end of the lever 108 downwardly and the pilot valve 103 is closed. Since the rod 104 moves a distance which is proportional to the amount of displacement of the nut 107, an amount of the hydraulic fluid or oil supplied from the piston member 102 to the cylinder 100, that is, an amount of stroke, is determined by the amount of rotation of the motor 114. Since the mechanism associated with the motor 115 is the same as that associated with the motor 114 and operates in the same manner, the same amount of rotation of the motors 114 and 115 can provide the same amount of stroke on either side and thus the lower working roll 5 can be moved in parallel relation all over and can be set at the same level.

When it is desired to move the lower rolls away from the upper rolls, the motors may be rotated in the opposite direction. Then, the nuts 107 move upwardly and the pilot pistons 105 are urged downwardly to provide communication between the conduits 113 and 112. T herefore, the lower rolls can go downwardly by gravity. When it is desired to operate only one of the two mechanisms, the magnetic clutch 116 may be deenergized and only the motor on the required side may be driven.

Although the invention has been described with regard to specific embodiments, it will be understood that the invention is in no way limited to such embodiments and various changes and modifications may be made without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. A rolling mill, comprising: a pair of cooperating working rolls; means for mounting one of said rolls for relative movement toward and away from the other of said rolls; fluid actuated power means for moving said one roll toward said other roll and including a piston and cylinder forming a working chamber; a source of fluid under pressure; a low pressure reservoir; roll position control means for determining the position of said one roll relative to said other roll including valve means having three positions for selectively connecting said chamber to said source in one position, for preventing connection of said chamber with said source and said reservoir in a second position, and for connecting said chamber with said reservoir in a third position; said control means including a lever, means drivingly connecting the central portion of said lever with said piston for displacement corresponding to displacement of said piston, and means drivingly connecting one end of said lever with said valve means for moving said valve means between said positions in response to corresponding displacement of said one end; said control means including actuator means for selectively displacing the opposite other end of said lever; and said control means normally being in a stable condition corresponding to the second position of said valve means.

2. A rolling mill, comprising, relatively movable rolls; fluid actuated piston means for moving said rolls relative to each other; fluid pressure and discharge line means for controlling the operation of said piston means; valve means in said line means for controlling the operation of said line means; a movable barrier means in said line means in series with said piston means and said valve means for preventing fiow of fluid past said barrier means and for producing a displacement corresponding to the displacement of said piston means when controlled by said line means; interconnecting means between said barrier means and said valve means for producing an actuating displacement of said valve means corresponding to displacement of said barrier means; said interconnecting means including adjustment means for selectively adjusting the relative positions of said barrier means and said valve means for changing the spacing of said rolls.

3. The device of claim 2, bypass fluid pressure and discharge conduit means for selectively fluid bypassing said valve means and said barrier means for directly controlling the operation of said piston means.

4. The device of claim 3, said interconnecting means including a lever drivingly connected between said barrier means and said valve means; said adjustment means including a screw and nut adjustment pivotally mounting a portion of said lever.

5. The device of claim 4, said screw and nut adjustment being at one end of said lever, the other end of said lever being connected to said valve means, and the central portion of said lever being pivotally connected to said barrier means.

6. The device of claim 5, said line means including an enlarged substantially tubular chamber and said barrier means comprising a piston sealingly mounted for reciprocation in said chamber.

7. The device of claim 6, said valve means being a spool type slidable valve having a first position connecting said piston means to said supply line means, a second position preventing connection of said piston means with said supply line means and said discharge line means, and a third position connecting said piston means with said discharge line means.

8. The device of claim 2, said interconnecting means including a lever drivingly connected between said barrier means and said valve means; said adjustment means including a screw and nut adjustment pivotally mounting a portion of said lever.

9. The device of claim 8, said screw and nut adjustment being at one end of said lever, the other end of said lever being connected to said valve means, and the central portion of said lever being pivotally connected to said barrier means.

10. The device of claim 2, said line means including an enlarged substantially tubular chamber and said barrier means comprising a piston sealingly mounted for reciprocation in said chamber.

11. The device of claim 2, said valve means being a spool type slidable valve having a first position connecting said piston means to said supply line means, a second position preventing connection of said piston means with said supply line means and said discharge line means, and a third position, connecting said piston means with said discharge line means.

12. A thrusting device for a rolling mill comprising a housing, a pair of working rolls rotatably supported in said housing, a pair of auxiliary rolls rotatably supported in said housing at positions outwardly of said working rolls so as to urge said working rolls inwardly from behind thereof, and a pair of hydraulic mechanisms each having a hydraulic cylinder operable to urge one of said working rolls toward the other through one of said auxiliary rolls, a pilot valve for controlling hydraulic pressure, a piston member interposed midway of a hydraulic fluid passage between said cylinder and said pilot valve for making a movement proportional to that of a ram in said cylinder, resetting means operatively associated with said piston member for actuating the same, and drive means for driving said resetting means.

References Cited UNITED STATES PATENTS 2,523,553 9/1950 Blain 72--245 3,157,073 11/1964 Blain 72-245 FOREIGN PATENTS 628,319 2/1963 Belgium.

973,254 9/1950 France.

644,957 4/1937 Germany.

CHARLES W. LANHAM, Primary Examiner.

G. P. CROSBY, Assistant Examiner. 

12. A THRUSTING DEVICE FOR A ROLLING MILL COMPRISING A HOUSING, A PAIR OF WORKING ROLLS ROTATABLY SUPPORTED IN SAID HOUSING, A PAIR OF AUXILIARY ROLLS ROTATABLY SUPPORTED IN SAID HOUSING AT POSITIONS OUTWARDLY OF SAID WORKING ROLLS SO AS TO URGE SAID WORKING ROLLS INWARDLY FROM BEHIND THEREOF, AND A PAIR OF HYDRAULIC MECHANISMS EACH HAVING A HYDRAULIC CYLINDER OPERABLE TO URGE ONE OF SAID WORKING ROLLS TOWARD THE OTHER THROUGH ONE OF SAID AUXILIARY ROLLS, A PILOT VALVE FOR CONTROLLING HYDRAULIC PRESSURE, A PISTON MEMBER INTERPOSED MIDWAY OF A HYDRAULIC FLUID PASSAGE BETWEEN SAID CYLINDER AND SAID PILOT VALVE FOR MAKING A MOVEMENT PROPORTIONAL TO THAT OF A RAM IN SAID CYLINDER, RESETTING MEANS OPERATIVELY ASSOCIATED WITH SAID PISTON MEMBER FOR ACTUATING THE SAME, AND DRIVE MEANS FOR DRIVING SAID RESETTING MEANS. 